PROJECT SUMMARY With the rising prevalence of autism spectrum disorders (ASD), increasing numbers of youth with ASD exit high school with each passing year. Adolescence and adulthood are times of significant risk for those with ASD; many face challenges in academic achievement, vocational stability, social connectedness, and mental health. These wide-ranging needs often result in significant public costs. Many of the vulnerabilities faced by adolescents and adults with ASD are also shared by women in the general population; thus, women with ASD might be doubly-vulnerable, by virtue of having an ASD and being a woman. Yet, the vast majority of studies on outcomes among adolescents and adults with ASD use samples that are primarily male, and thus the unique needs of women with ASD are mostly unknown. Further, the extant research on sex differences in ASD is fragmented, with no over-arching framework to guide integration of findings, and with little knowledge about potential psychosocial mechanisms responsible for sex differences that emerge. The objective of this research is to conduct secondary data analysis on three existing datasets, to develop a new evidence base on the academic, self-determination, vocational, social, health, mental health, and service utilization outcomes of adolescent and adult women with ASD. We will examine sex differences in these outcomes, allowing us to identify areas where women are uniquely vulnerable as well as areas in which vulnerabilities are shared with men with ASD. We propose three tightly-integrated Specific Aims: (1) We will use the Center on Secondary Education for Students with Autism Spectrum Disorders (CSESA) database of 546 well-characterized adolescents with ASD (20% female) to examine sex differences in school achievement, self-determination, vocational readiness, social participation, mental health conditions, and service use; (2) Using data to be collected in 2016/2017, we will examine an Interactive Autism Network (IAN) national sample of adults with ASD (expected n ? 260, 65% female) and caregivers of adults with ASD (expected n ? 150, 25% females) to test for sex differences in post-secondary educational and vocational experiences, service receipt, physical and mental health conditions, social participation, and discrimination experiences; and (3) We will use electronic health records from the Marshfield Clinic ? one of the largest, private, multispecialty group practices in the United States ? to examine sex differences in physical and mental health conditions and healthcare utilization for adults with an autism diagnosis as identified in their medical records (approximate n = 1,000, ~25% female). For both the CSESA and Marshfield datasets, we will examine if sex differences are more apparent over time or with increasing age. For all datasets, possible psychosocial mechanisms of sex differences will be explored (e.g., discrimination, health care utilization). Completion of the Aims will result in an evidence-base to guide future research and interventions focused on better serving women with ASD during adolescence and adulthood.